The present invention relates to an airbag apparatus mounted on a vehicle such as an automobile or the like, for restraining an occupant at a time of a collision, and more specifically, it relates to an airbag apparatus in which an airbag-fixing portion is protected from a high-temperature gas for developing the airbag (hereinafter the gas for developing the airbag is referred to as the gas for development) in the vicinity of the airbag-fixing portion on a vehicle body side, and in which a fixing strength for fixing the airbag is improved.
An airbag is provided with a blowing inlet through which a gas for development is blown into the airbag, and a peripheral edge portion of the blowing inlet is fixed to a member such as a retainer or the like provided on a vehicle body side.
Hitherto, in order to increase the fixing strength for fixing the airbag, it is well known that the airbag is sandwiched between a retainer where an inflator is inserted, and a pressing ring, and a chain-shaped seam is formed around a periphery of the blowing inlet, and the chain-shaped seam is engaged with a bore diameter surface of the retainer (for example, refer to Patent Document 1).
In the technology described in the Patent Document 1, an inner peripheral edge portion and an outer peripheral edge portion of a main part of the pressing ring having a flat plate shape, are risen in flange-shapes, respectively, so that a cross sectional surface shape thereof seen by cutting the pressing ring in a radial direction is formed to have an approximately C-shape.
Further, it is well known that a pressing member having a ring shape is formed with a spring steel so that the airbag is securely fixed with a simple structure, and the airbag is sandwiched between the pressing member and a base plate by utilizing the elasticity of the spring steel (for example, refer to Patent Document 2).
Furthermore, in the Patent Document 2, it is described that the gas for development, which is blown out from the inflator on an upper surface of a base plate portion, is introduced by means of bending an inner edge of the base plate portion of the pressing member downward, and the airbag is smoothly developed.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2-262446
Patent Document 2: Japanese Unexamined Patent Application Publication No. 7-291074
However, in the technology described in the aforementioned Patent Document 1, since a part of the gas for development, which is blown out from the inflator sometimes, flows into a space between the pressing ring and the airbag, a base cloth panel and the chain-shaped seam constituting the airbag are exposed to high-temperature gas for development after blown out from the inflator, so that a sufficient consideration is required for securing a heat tolerance.
On the other hand, in the technology described in the Patent Document 2, since a fixing operation for the airbag mainly depends on a sandwiching force generated by means of the elasticity of the pressing member between the pressing member and the base plate, the fixing strength for fixing the airbag becomes lower than that in the technology in the Patent Document 1, in which the chain-shaped seam is engaged with the member on the vehicle body side.
The present invention has been made in view of the above-described problems and it is an object of the present invention to provide an airbag apparatus, in which the airbag-fixing portion is protected from a gas for development, and in which a fixing strength for fixing the airbag is improved.
Further objects and advantages of the invention will be apparent from the following description of the invention.